This is the discussion thread for the 2018 UK Puzzle Championship. It will also act as the second qualifier for the UK A team competing at the World Puzzle Championships in Prague, Czech Republic to be held on the 4th-11th November 2018 (note that these dates also include time for the World Sudoku Championships).

Am I missing something in the rules for Fillomino (Different Shapes)? The example puzzle seems not to have a unique solution - one can replace the 4 and 3 polyominoes from the lower-left corner of the given solution with a single 7 polyomino without appearing to break any of the constraints.

Am I missing something in the rules for Fillomino (Different Shapes)? The example puzzle seems not to have a unique solution - one can replace the 4 and 3 polyominoes from the lower-left corner of the given solution with a single 7 polyomino without appearing to break any of the constraints.

I think I can find four solutions in total, in fact.

I made the example and I didn't think about the possibility of putting a 7 in, so that definitely would give an alternate answer. For that example the group of 1,2,3,3,4,4,4,5,5,5. The competition puzzle does have a unique solution (indeed they all do).
Apologies for this poor example.

Lovely looking IB. I reckon I’ll have a wide range of puzzles to get into.

I’m intrigued by Laser, but I don’t understand either the mirrors or the answer key.

What are “one cell sections”?
When it talks about mirrors, are they very small, just at the intersection of vertical and horizontal squares, or a cell wide? The numbers that count mirrors, do they count both horizontal and vertical mirrors on that line?

Lovely looking IB. I reckon I’ll have a wide range of puzzles to get into.

I’m intrigued by Laser, but I don’t understand either the mirrors or the answer key.

What are “one cell sections”?
When it talks about mirrors, are they very small, just at the intersection of vertical and horizontal squares, or a cell wide? The numbers that count mirrors, do they count both horizontal and vertical mirrors on that line?

I've added a file with the laser solution in with the mirrors marked (in red). The numbers that count the mirrors do count both horizontal and vertical ones. The mirror is basically at the intersection.
For the answer key, the laser will cross cells across the diagonal. The count is the number of single cells that the path crosses before hitting a mirror and making a turn or leaving the grid. Each of the single cell sections has been marked in this version.

I also found the mirror terminology confusing. In my reading of the rules, I think you can, instead of thinking about mirrors, simply say that the "mirror clues" refer to the number of intersections at which the laser turns instead of going straight. This includes at the boundary of the grid.

The one-cell sections are sections of the laser passing through exactly one cell before turning.

That interpretation gave the example puzzle a unique solution which was the same as the one in the IB.

(I see that Liane has posted an official answer while I was typing - you may still find the mirrorless interpretation useful)

Yes, mirrors just refer to wherever the line changes direction.
Laser is an old CrocoPuzzle type - if you want to test your understanding of the rules (or just practice) then look through the archive at https://www.croco-puzzle.com/Raetselspa ... /index.php
It's also the main place to find ABC Box, but they also have many standard types.

Anyone would think you are trying to help your opposition James
Good luck to everyone competing in the championship this weekend and I hope that you all enjoy it. I certainly have whilst testing all the puzzles and putting it all together.

I’ve been gamely plodding ahead with the puzzles I didn’t get in the time limit.

The Fillomino different shapes has me completely baffled. I broke it in a few places. What should I have been doing?

The Finnish snake, I managed to rule out a few squares on the corners of the diagonally adjacent givens. Then it broke. What does the finished snake look like?

Finally the laser. I feel like the 5 at the top is the place to start, but I can’t even find one solution with five mirrors on that line. Pleased I didn’t find time to look at it. Anybody got a finished puzzle I can see?

Aside from some obvious initial moves, the starting point I used for the Fillomino during the contest was to count the given 4s. There are plenty of them, and only 5 possible different shapes. You can work out which ones connect, and make some deductions about which shapes can or cannot go where. The I-shaped piece is possible to place very early on, in particular.

To get yourself going on the Laser, note that the mirrors indicated by the second "5" clue on the right completely fill the horizontal line (there are only 5 intersections on that line reachable by the laser). One of them intersects with the first "2" clue along the bottom, so the laser cannot travel from the start to the top-left area of the grid without having too many mirrors in that vertical line. That then resolves how the laser travels through the top couple of rows of the grid, since without the top-left corner, there are exactly 5 usable mirror points for the first horizontal "5" clue.

The Fillomino different shapes has me completely baffled. I broke it in a few places. What should I have been doing?

Fillomino - you can see that all options for 2,3 and 4 pieces must be used and you can work out how many 5's and 6's there must be so there must be a single cell somewhere. Look at the bottom right corner - you should be able to place the single cell and make progress with the 5's and 6's. Working with the options for the 4's - L, I, T, S, O pieces and you should then be able to continue to make progress.

Finally the laser. I feel like the 5 at the top is the place to start, but I can’t even find one solution with five mirrors on that line. Pleased I didn’t find time to look at it.

Looking at the top 5 there are 6 places that a mirror could be positioned and for the 4 on the row below there are five places. If you look at the lower 5 then there are just five places that the mirrors can be so you can mark each of those nodes as having a mirror (though you don't know the orientation). Going back to the top 5 - if there was to be a mirror on the left hand side of the grid then that would force mirrors on the lines above and below it on the next grid line along so that would break the 2 clue on that line as you already know that there will be a mirror on the intersection with the other 5. You can then start to draw in part of the laser path from the right hand side using the mirrors for the top 5 which will then identify where the mirrors must go on the 4 line. You should then be able to make some more progress from that point. I can talk you through a bit more if needed.